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Iodine is an essential mineral that plays an important role in maintaining the health and function of your thyroid gland.
The thyroid gland is a butterfly-shaped organ located in your neck that produces specific hormones that help regulate growth and metabolism (1).
Iodine functions as a building block of the two main thyroid hormones — triiodothyronine (T3) and thyroxine (T4) (
If your intake of iodine is too low, you can end up with low levels of thyroid hormone in your blood.
Insufficient levels of thyroid hormones can lead to symptoms like neck swelling, fatigue, dry skin, hair loss, difficulty regulating body temperature, and weight gain (1).
Iodine is naturally found in a variety of foods, such as seafood, dairy products, eggs, and seaweed.
It may also be found in grains and some fruits and vegetables. However, the exact amount is primarily dependent upon the iodine levels of the soil in which the crop was grown (1).
Given the variability in iodine levels in many plant-based foods, some countries have iodine-fortified foods available, such as iodized salt, to prevent deficiencies.
Even so, certain groups of people are at an increased risk of iodine deficiency, including (1):
- people who are pregnant
- people living in places where the soil is iodine-depleted
- people following strict vegan and vegetarian diets
- people who avoid or have limited access to iodized salt
If you have difficulty getting enough iodine in your diet, your healthcare provider may recommend that you take an iodine supplement.
The supplements on this list were chosen according to ingredient quality, price, and manufacturing standards.
Here are the 10 best iodine supplements for 2021.
A note on price
General price ranges with dollar signs ($ to $$$) are indicated below. One dollar sign means the product is rather affordable, whereas three dollar signs indicate a higher price range.
Generally, prices range from $0.06–$2.32 per serving, or $8–$69.70 per container, though this may vary depending on where you shop.
Note that serving sizes vary by product.
- $ = under $0.25 per serving
- $$ = $0.25–$0.50 per serving
- $$$ = over $0.50 per serving
If you’re looking for a basic, high quality iodine supplement, look no further, as these are among the best on the market.
Thorne is a reputable brand known for producing a variety of high quality, allergy-friendly nutritional supplements.
Its iodine supplement is designed to support thyroid health using a combination of 225 mcg of potassium iodide, or 150% of the RDI, and 500 mg of tyrosine — an amino acid your body uses to produce thyroid hormones (
This supplement is free of sugar, artificial sweeteners, and major allergens like gluten, wheat, tree nuts, dairy, and soy.
All of Thorne’s nutritional supplements are tested for purity and potency, and their manufacturing facilities are certified by multiple regulatory agencies, including NSF International and the Therapeutic Goods Administration (TGA).
Some people may benefit from supplementing with high doses of iodine short term, and these are some great options to choose from.
Keep in mind that you should not attempt to take exceptionally high doses of iodine without guidance from a qualified healthcare provider.
Each of Life Extension’s Sea-Iodine capsules provides 1,000 mcg of iodine, or 667% of the RDI, sourced from a combination of kelp and potassium iodide.
All of Life Extension’s ingredients are meticulously studied, and their final products are manufactured in facilities certified by NSF International, so you know you’re always getting a high quality supplement.
For the sake of transparency, Life Extension also provides you a certificate of analysis for every batch of supplements they produce, so you can see exactly what’s in the product you’ve purchased.
Swanson’s Triple Iodine Complex supplement provides a high dose of 12,500 mcg of iodine, or 8,333% of the RDI, in the form of potassium iodide, sodium iodide, and kelp-derived iodine.
All of Swanson’s supplements are tested for purity and potency in-house, as well as by third-party laboratories. What’s more, all of their manufacturing facilities are certified by the Food and Drug Administration (FDA).
Designs for Health’s Iodine Synergy supplement contains 10,000 mcg of iodine, or 6,670% of the RDI, in the form of potassium iodide, plus 40 mcg of selenium, a nutrient that functions as an antioxidant and aids thyroid hormone metabolism (
It’s vegetarian-friendly and free of most major allergens, including dairy, soy, and gluten. It also comes in a glass bottle for easy recycling.
Designs for Health is a reputable brand that maintains stringent quality standards during each step of the manufacturing process. All products are tested for purity, potency, and safety, and all of their production facilities are FDA certified.
Seaweed is one of the richest natural, plant-based sources of iodine.
If you prefer taking supplements sourced from whole food ingredients, you may want to try one of these options, which are made exclusively with iodine from a type of seaweed known as kelp.
Iodine is a very important nutrient for sustaining a healthy pregnancy.
Prenatal supplements contain vastly different types and quantities of nutrients, but many do not contain iodine at all.
An article published in the journal of the American Academy of Pediatrics states that although most pregnant and nursing mothers take prenatal supplements, only 15–20% are taking one that contains iodine (4).
Here are two high quality options that do.
When choosing a nutritional supplement, you’ll want to consider a variety of factors, including the price, quality, ingredient content, and dosage.
Certain brands are more expensive than others, but price isn’t necessarily a good indicator of quality.
In certain countries, such as the United States, nutritional supplements are not as tightly regulated as medications.
Thus, the safest option is to stick with supplements that are produced by reputable companies that maintain high manufacturing standards and routinely test their products for purity and potency.
You also want to inspect the ingredient label. If there are any specific ingredients you’re avoiding, such as added sugar, animal products, artificial sweeteners, or allergens, always check the ingredient list before purchasing.
Finally, you want to evaluate the dosage.
Supplements often contain more than the recommended daily amount of a nutrient, so you want to be careful you don’t accidentally consume too much.
Conversely, if your healthcare provider recommends that you take a high dose, make sure you choose one that provides an adequate amount to meet your needs.
Useful supplement shopping guides
Check out these two articles to help make supplement shopping a breeze:
It’s important to consult your healthcare provider prior to taking an iodine supplement, as getting too much can lead to very serious side effects.
Overconsuming iodine can lead to symptoms similar to those of iodine deficiency, such as neck swelling, fatigue, and weight gain. More serious side effects include inflammation of the thyroid gland and thyroid cancer (1).
Acute iodine toxicity is rare but can occur if high doses are taken without medical supervision. Symptoms of iodine toxicity include nausea, vomiting, fever, diarrhea, a weakened heartbeat, and burning throat and mouth (1).
The RDI of iodine for healthy adults is 150 mcg. If you are pregnant or breastfeeding, the daily dose increases to 220 mcg and 290 mcg, respectively (1).
Most serious adverse reactions are seen when iodine intakes exceed 1,100 mcg per day, or 733% of the RDI, for an extended period of time. Hence, you should not attempt to take doses higher than the recommended daily amount without medical supervision (1).
Iodine is an essential mineral that supports the proper function of your thyroid gland.
Your thyroid gland plays a critical role in producing hormones that regulate growth and metabolism throughout your life.
If you suspect you have low iodine or may be at risk of developing iodine deficiency, you should consult your healthcare provider to determine whether an iodine supplement is right for you.
There are countless supplement options available. When choosing one that is best for you, always be sure to consider the price, ingredient content, dosage, and overall quality before purchasing.